Showing papers on "Countercurrent exchange published in 1972"

Analysis of Membrane Separation Parameters. II. Counter-current and Cocurrent Flow in a Single Permeation Stage

Abstract: Analytical expressions are presented for calculating the extent of separation of binary gas mixtures achievable in a permeation stage, as well as the required membrane area, when the high- and low-pressure streams in the stage flow either countercurrently or cocurrently to each other. The derivations are similar to those of Oishi et al., but are cast in a form suitable for computer calculations. The results of a parametric study on the separation of oxygen from air are presented for four different flow patterns inside the stage: (a) countercurrent flow, (b) cocurrent flow, (c) cross-flow, and (d) perfect mixing. In the first three cases it is assumed that no mixing occurs on the two sides of the stage (or membrane). The type of flow in the permeation stage can have a significant effect on the degree of separation, but has relatively little effect on the membrane area at low separation factors. Countercurrent flow is the most efficient flow pattern, whereas perfect mixing is the least efficient on...

Hydrocarbon conversion process utilizing a moving bed reactor

Abstract: A MOVING BED OF A CATALYST WHICH DEACTIVATES IN A ZONAL MANNER IS TRANSFERRED DOWNWARD THROUGH A MULTIPASS RADIAL FLOW REACTOR WHILE A HYDROCARBON FEED STREAM FLOWS IN A STEPWISE COUNTERCURRENT FASHION ACROSS THE CATALYST. TO PROVIDE UNIFORM CONVERSION AND MAXIMUM USAGE OF THE CATALYST, A SONE OF ACTIVE CATALYST AND A ZONE OF DE- ACTIVATED CATALYST ARE BOTH MAINTAINED ACROSS THE HEIGHT OF A SINGLE SELECTED PASS BY CONTROLLING THE CATALYST TRANSFER RATE.

Ultrasonic cleaning of resin

Abstract: A method of cleaning contaminated resins for reuse comprises establishing a countercurrent flow between the contaminated resin and a carrier fluid for carrying the removed contamination from the resin and applying ultrasonic energy to the countercurrent flow with the countercurrent flow being conducted so that a region of turbulence is achieved where the ultrasonic energy is applied. A cleaning apparatus has means for introducing a contaminated resin and means for introducing a carrier fluid to a treatment zone in a countercurrent flow, means for collecting cleaned resin from the treatment zone, means for removing the carrier fluid from the treatment zone, and ultrasonic energy means for applying an ultrasonic energy field to the countercurrent flow in the treatment zone.

Foam Fractionation in a Stripping Column

Abstract: Experiments with stripping foam fractionation columns indicate that within the range of variables studied, stripping lengths of 10 to 150 cm have negligible effect on separation. These experimental results cannot be explained adequately by the transfer unit approach. A physical model is proposed wherein the stripping length consists of two mixing regions and a countercurrent flow region in between. Negligible solute transfer is assumed in the countercurrent flow region. This model is applied to explain the experimental data.